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Q4 (Easy): Fill in the blanks: (i) Nalini observed brown deposits on her cycle handle. The brown deposits are due to ______, and this is a ______ change. (ii) Folding a handkerchief is a ______ change and can be ______. (iii) A chemical process in which a substance reacts with oxygen with evolution of heat is called _______, and this is a ________ change. (iv) Magnesium, when burnt in air, produces a substance called ______. The substance formed is _______ in nature. Burning of magnesium is a _______ change.
💡 Word Box: rusting | physical | reversed | combustion | chemical | magnesium oxide | basic
Answer:
We have studied that
rusting
forms
new substances
and
combustion
produces
heat and light
. This is why these are chemical changes.
- (i) rusting , chemical - iron oxide forms
- (ii) physical , reversed - same handkerchief remains
- (iii) combustion , chemical - new substances form
- (iv) magnesium oxide , basic , chemical - new compound forms
